Ruger AR-556 .450 Bushmaster 5-Round Magazine

.450 Bushmaster is a big-bore straight-wall cartridge that feeds very differently from 5.56 NATO. Ruger's factory AR-556 .450 Bushmaster magazine is a 5-round steel magazine, part 90679, built for the straight-wall cartridge instead of standard double-stack 5.56 geometry.

The 5-round capacity fits the cartridge's hunting role and the way .450 Bushmaster stacks in AR-pattern magazines. The steel body and cartridge-specific follower geometry keep the wide .452-caliber projectile aligned for feeding, which matters more than maximum capacity in straight-wall deer and hog rifles.

For hog and deer hunters in straight-wall states using a .450 Bushmaster AR-15, two or three dedicated 5-round magazines is the practical loadout. The cartridge is too punishing and expensive to shoot in volume, and reliability is more important than squeezing a few extra rounds into a modified 5.56 body.